Thursday, January 22, 2015

Stephanie RukowiczJust in time for seed ordering season, some food for thought. Which varieties of fruits and vegetables offer the most nutrition? Last month, I attended the Selecting Seeds for Healthy Vegetables workshop at the Penn State Extension office. It featured discussion of Jo Robinson’s Eating on the Wild Side: The Missing Link to Optimum Health and an investigation into which seed vendors offer specific nutrient dense varieties. The majority of attendees were urban farmers looking to select the best varieties to grow and offer to their communities.

As a broad summary of the text, Robinson discusses how, historically, cultivated plants have been bred for maximum flavor, appearance, storage and durability, with little thought given to nutritional content. Over the past several thousand years, nutrition has been bred out of our food. Only recently have scientists started investigating bioavailability of phytonutrients (like antioxidants), sugars, and proteins. Workshop attendees spent time researching which specific varieties noted by Robinson are currently offered in 2015 seed catalogs. High Mowing Organic Seeds included the greatest overall number of varieties listed by Robinson (see below for a catalog excerpt of High Mowing's beet varieties).

The four circled beet varieties are said to be highest in phytonutrient content
(except from page 8 of High Mowing Organic Seeds 2015 Catalog).

Robinson generalizes that the closer a variety looks or tastes to its relative found in the wild, the more nutritious it should be. Often this means that a more nutritious variety is more colorful in appearance (think purple potatoes over white) and possibly less sweet or more bitter (think Granny Smith over Golden Delicious). She recognizes that there are exceptions to the rule, noting the example of white-fleshed peaches having twice the nutrients than yellow-fleshed. The choices are not always intuitive, so she recommends shopping with a list to select the most nutritious varieties.

Thursday, January 8, 2015

I consult with urban dwellers on their horticultural needs. Recently, I met a client with two gorgeous mature white oaks flanking the entrance of his Center City residence. One of the trees had a fungal growth at the base, about 12 inches in breadth and maybe 1.5 inches in height, and it had been routinely removed for appearance sake by the owner's house staff. The tree had an overall strong canopy. Even though the wound was shallow and there was little wood rot in the trunk, I knew the tree was dying.

(courtesy of RHS)

The treefungus is Ganoderma sp., commonly known as shelf or bracket fungi. The fungus causes what is called butt rot and root rot. It has significant impact on oaks, and potentially especially those near the end of their life expectancy of 65-85 years old - note this expectancy is based on trees in naturalized settings, not urban tree pits. The visible fungus is a fruiting body, which means that the fungus is systemic.

If it helps, you can visualize a flowering shrub with infected roots and flowers in bloom- the fungus has established in the base and/or roots of the tree and the visible fungus is the flower in bloom. There is no cure and removing the fruiting body has little to no impact on control of spread, outside of reducing the number of spores released that may enhance disease spread from say tens of millions to just millions in number. The plant is dying from the roots outward. Eventually, the tree will show signs of sickness like leaf dieback and discoloration. Based on the literature, the lifespan of a tree with this fungus is something on average like between several and ~ 10 years. In natural settings, most trees with this rot meet their end from breakage or toppling in winds/storms.

The client was a sad about losing the trees and although the tree was leafing out well and he could play a waiting game for the infected tree to die- and infect the neighboring oak, he choose to seek removal estimates from professional arborists. The arborist concurred with my diagnosis and outlook and recommended replacement trees that are probably familiar to many as reliable street trees.

Thursday, January 1, 2015

The Philadelphia Water Department
(PWD) has made a strong commitment to controlling erosion and excess run-off in
the city, including some imaginative and innovative large-scale projects. I
found an inexpensive, simple PWD project I could do in my own yard with just a
shovel!

The house I moved
into a few years ago had a half-sized basketball court in the backyard. I
briefly considered removing it until I calculated the expense and work
involved. Then I decided to

make the best of it. However, after a couple of
heavy rains, I realized I would have to do something about the rain water
run-off.

I consulted a web site from the PWD with guidelines for building a rain
garden.

A rain garden is a swale or depression surrounded by a berm,
positioned where rain run-off can be temporarily held until it can infiltrate
into the ground. Rain from impervious
surfaces such as roofs, parking lots, or the occasional basketball court can be
diverted into the garden rather than causing erosion or ending up in the storm
sewer. The water is held only temporarily. A rain garden is not a pond or water
feature. The water will drain into the ground over a fairly short time.

There is a link on the PWD site for a PDF with guidelines
for building a garden. It lists some guidelines for the selection of a good
site:

1. The garden should be at least 10 feet from building foundations.
This guideline is the most important to follow, even if it means that rain
garden may fall short in some of the other considerations.

2. Position the garden to accommodate most, if not all of the water
draining from the surface. In my case, if I built my garden along the
entire edge of the court, I would place it too close to the foundation of my
house. So I restricted the size accordingly.

3. The garden should be at least 20% of the surface area of the drainage
area. The area of the space I had available was just slightly over 20%, but
even if I had not been able to build a garden quite so large, I figured that
whatever I did would be helpful.

4. Drainage should be adequate to allow infiltration of rain water
collected. The PWD web site also includes a simple way to test this. Here's
the URL:

Remove the top and bottom of a coffee can and then push or
hammer the can a couple of inches into the ground. Measure the side of the can above
the ground and fill the can with water. Start a timer andone inch per hour, the site is adequate.

calculate the time it
takes for the water to drain from the can. Repeat this test a few times to
assure accuracy. If the drainage rate is at least

Now some guidelines for shaping the garden.

1. The depth of the
swale should be 6-8 inches.

2. The height of the berm should be at least 4-6 inches.

3. The height of the
berm above grade, should be no more than one-third the width of the berm.
My berm was 3 or 4 inches high, so I made sure it was at least a foot wide.

To construct the garden, I placed a row of stakes along the
court, and another row on the opposite side of the garden. I ran string between
the rows of stakes and adjusted it to be level with the court. Then I measured
the stakes at the outside of the garden for the height of the berm

A note of caution: Be sure it is safe to dig! Contact Pennsylvania One
Call system by dialing 811 to be sure you are not disrupting utility lines!
Hitting one would be extremely dangerous!

As I dug out the swale, I used a ruler to measure down from
the string. As I removed the dirt from the swale, I placed it on the berms.

When I had the garden shaped correctly, I used a hose at
full force to watch where the water flowed

from all angles of the court.

The final consideration: Which plants to use? All the usual
considerations for planting a garden apply with one notable addition: the soil
will be very wet at times, so be sure to choose plants that can tolerate that. The
PWD pamphlet has a list of some possible native plants, but I decided to go
with what I had available.

A friend was splitting a large patch of Japanese Iris, a
plant that can tolerate high moisture. Another friend was splitting Athyrium or
Lady Fern and I used those as well.

And the results? A resounding success! This inexpensive, simple project has drastically reduced the run-off from the court, and I have a garden that's lovely to look at.

Philadelphia master Gardeners

The mission of the Penn State Extension Master Gardener volunteer program is to support the Penn State Cooperative Extension by utilizing research-based information to educate the public on best practices in consumer horticulture and environmental stewardship. Master Gardeners serve their communities by helping the public with horticulture, gardening, and pest management by providing educational workshops , answer gardening questions on the hortline, and provide school children and adults with gardening programs.